JS多个异步请求 按顺序执行next实现解析

function nextRegister(){
      var args = arguments;
      var count = 0;
      var comm = {};
      function nextTime(){
        count++;
        if(count < args.length){
          if(args[count] && Object.prototype.toString.call(args[count]) == '[object Function]'){
            args[count](comm,nextTime);
          }
        }
      }
      if(args[count] && Object.prototype.toString.call(args[count]) == '[object Function]'){
        args[count](comm,nextTime);
      } 
    }　

/*
     comm:多个函数，公用的变量
     next:调用下一个函数
     * */
    function fn1(comm,next){
      console.log('1');
      comm.age = 20;
      next();
    }
    function fn2(comm,next){
      next();
      console.log('2');
      console.log(comm.age);
    }
    function fn3(comm,next){
      console.log('3');
    }
//开始执行迭代
nextRegister(fn1,fn2,fn3);